Breakpoints in @workflow.run Not Triggering in Temporal Python SDK (but work in Activities)

Community Support
1

I’m running a Temporal Python worker in debug mode (PyCharm), and I’m able to hit breakpoints inside @activity.defn methods without any issues. However, breakpoints inside the @workflow.run method do not trigger at all, even though:

  • The workflow code is definitely executing (I see print() output)
  • The worker is running in the same process under the debugger
  • I am starting the workflow using await client.execute_workflow(…) from pycharm as well, using debug mode.
  • using latest temporal
  • all this is running on my macbook pro (local dev machine)
  • and set debug_mode when creating the worker.
worker = Worker(
        client,
       .....
        debug_mode=True,
    )

@workflow.defn
class MyScanner:
    @workflow.run
    async def run(self) -> None:
        print("Entered run")  # This shows up in logs
       # none of the breakpoints below triggers.
        if <...>:

What I’ve tried:

  • Verified PyCharm is in debug mode (confirmed by breakpoints hitting in activities)
  • Tried restarting workflow execution with new workflow_id to avoid replay. also restarted temporal, pycharm
  • Confirmed print() calls inside run() do show output
  • I also set TEMPORAL_DEBUG=true as an environment variable (its outputting as true in the worker logs), but nothing changes.

Question:

  • Why aren’t breakpoints working in @workflow.run despite everything running in-process? Is this a limitation of the Temporal Python SDK’s? Any known workarounds?